Briefly, α-V2O5 nanowires were drop-cast onto a silicon nitride X-ray grid (Norcada) after ultrasonication in 2-propanol. On-substrate lithiation was achieved by direct reaction with a molar excess of n-butyllithium (0.01 M) in heptane within an Ar-filled glovebox environment as per
ζ-V2O5 nanowires were collected from coin cells discharged to specific voltages. After discharge to desired voltages, the coin cells were disassembled, and the electrodes were washed with copious of dimethyl carbonate. The electrodes were subsequently dried overnight in an Ar-filled glovebox (H2O, O2 < 0.1 ppm). Prior to the STXM measurements, a portion of the active electrode material was ultrasonicated in 2-propanol to create a dispersion from which nanowires could be transferred to an X-ray–transparent silicon nitride grid (Norcada) using drop casting. Lithiated nanowires (both ζ- and α-V2O5) were washed with anhydrous heptane to remove excess unreacted n-butyllithium or electrolyte to prevent the formation of undesirable surficial LixOy species. The grids were sealed under vacuum for transport to the Canadian Light Source for STXM measurements.
STXM measurements were collected at the spectromicroscopy beamline 10D-1 of the Canadian Light Source in Saskatoon, SK, utilizing a 7-mm generalized Apple II elliptically polarizing undulator source. X-ray absorption spectra were acquired across the V L2-, V L3-, and O K-edge elemental absorption edges at each pixel by scanning the incident X-ray energy in the range 510 to 560 eV. The image stack was aligned using a cross-correlation method contained within the aXis2000 software suite. Spectra were pre- and postedge normalized using the Athena software suite to facilitate comparison.
ζ-V2O5 nanowires were collected from coin cells discharged to specific voltages. After discharge to desired voltages, the coin cells were disassembled, and the electrodes were washed with copious of dimethyl carbonate. The electrodes were subsequently dried overnight in an Ar-filled glovebox (H2O, O2 < 0.1 ppm). Prior to the STXM measurements, a portion of the active electrode material was ultrasonicated in 2-propanol to create a dispersion from which nanowires could be transferred to an X-ray–transparent silicon nitride grid (Norcada) using drop casting. Lithiated nanowires (both ζ- and α-V2O5) were washed with anhydrous heptane to remove excess unreacted n-butyllithium or electrolyte to prevent the formation of undesirable surficial LixOy species. The grids were sealed under vacuum for transport to the Canadian Light Source for STXM measurements.
STXM measurements were collected at the spectromicroscopy beamline 10D-1 of the Canadian Light Source in Saskatoon, SK, utilizing a 7-mm generalized Apple II elliptically polarizing undulator source. X-ray absorption spectra were acquired across the V L2-, V L3-, and O K-edge elemental absorption edges at each pixel by scanning the incident X-ray energy in the range 510 to 560 eV. The image stack was aligned using a cross-correlation method contained within the aXis2000 software suite. Spectra were pre- and postedge normalized using the Athena software suite to facilitate comparison.
